B>update (select field1, field2, field3
B>    from Table1 A
B>    where (field1, field2, field3) in (Select B.field1, B.field2, max(B.field3) 
B>        From Table1 B
B>        Where b.field1 = a.field1
B>        and b.field2 = a.field2))
B>Set ....
B>